diff --git a/src/js/models/panel_model.js b/src/js/models/panel_model.js
index 7e3c02a67..8d2495e0d 100644
--- a/src/js/models/panel_model.js
+++ b/src/js/models/panel_model.js
@@ -90,7 +90,6 @@
             var newData = {'imageId': data.imageId,
                 'name': data.name,
                 'sizeZ': data.sizeZ,
-                'theZ': data.theZ,
                 'sizeT': data.sizeT,
                 'orig_width': data.orig_width,
                 'orig_height': data.orig_height,
@@ -106,10 +105,13 @@
                 'deltaT': data.deltaT,
             };
 
-            // theT is not changed unless we have to...
+            // theT and theZ are not changed unless we have to...
             if (this.get('theT') >= newData.sizeT) {
                 newData.theT = newData.sizeT - 1;
             }
+            if (this.get('theZ') >= newData.sizeZ) {
+                newData.theZ = newData.sizeZ - 1;
+            }
 
             // Make sure dx and dy are not outside the new image
             if (Math.abs(this.get('dx')) > newData.orig_width/2) {
diff --git a/src/js/views/modal_views.js b/src/js/views/modal_views.js
index db1ef93ca..2961a5db0 100644
--- a/src/js/views/modal_views.js
+++ b/src/js/views/modal_views.js
@@ -292,8 +292,11 @@
                     'datasetName': data.meta.datasetName,
                     'pixel_size_x': data.pixel_size.valueX,
                     'pixel_size_y': data.pixel_size.valueY,
+                    'pixel_size_z': data.pixel_size.valueZ,
                     'pixel_size_x_unit': data.pixel_size.unitX,
+                    'pixel_size_z_unit':data.pixel_size.unitZ,
                     'pixel_size_x_symbol': data.pixel_size.symbolX,
+                    'pixel_size_z_symbol': data.pixel_size.symbolZ,
                     'deltaT': data.deltaT,
                 };
                 self.newImg = newImg;
@@ -347,8 +350,8 @@
             json.selThumbSrc = WEBGATEWAYINDEX + "render_thumbnail/" + json.selImg.imageId + "/";
 
             // minor attributes ('info' only)
-            var attrs = ["sizeZ", "orig_width", "orig_height"],
-                attrName = ['Z size', 'Width', 'Height'];
+            var attrs = ["orig_width", "orig_height"],
+                attrName = ['Width', 'Height'];
 
             if (this.newImg) {
                 json.newImg = this.newImg;
@@ -380,6 +383,26 @@
                 } else {
                     json.comp.sizeT = true;
                 }
+
+                // special message for sizeZ
+                if (json.selImg.sizeZ != json.newImg.sizeZ) {
+                    // check if any existing images have theZ > new.sizeZ
+                    var tooSmallZ = false;
+                    sel.forEach(function(o){
+                        if (o.get('theZ') > json.newImg.sizeZ) tooSmallZ = true;
+                    });
+                    if (tooSmallZ) {
+                        json.messages.push({"text": "New Image has fewer Z slices than needed. Check after update.",
+                            "status": "danger"});
+                    } else {
+                        json.messages.push({"text":"Mismatch of Z slices: should be OK.",
+                            "status": "success"});
+                    }
+                    json.comp.sizeZ = false;
+                } else {
+                    json.comp.sizeZ = true;
+                }
+
                 // compare channels
                 json.comp.channels = json.ok(true);
                 var selC = json.selImg.channels,